The Notch receptors coordinate cell to cell communication, cell growth, and determine cell fates. Malfunctions in Notch signaling have been linked to a range of diseases including cancer, which has spurred interest in understanding its molecular mechanisms of activation. The central hypothesis of the proposed work is that physical aspects of the Notch ligand-receptor interaction, mechanotransduction, and spatial arrangement, actively provide a molecular mechanism for signal regulation. The long-term goal of this proposal is to develop a complete understanding of how spatio-mechanical inputs can exert regulatory control over biochemical signaling processes. We seek a fundamental understanding of how the extracellular environment influences a cell's intracellular chemical signaling. To achieve this goal, we propose a highly multidisciplinary, hybrid physical and biological approach aimed at deconstructing how the Notch receptor cleavage is sensitive to clustering, mechanics, and spatial arrangement. These questions cannot be addressed unless a new approach is introduced to manipulate and to investigate Notch in individual living cells. We will employ surface-based activation of Notch to recapitulate its innate two-dimensional geometry with the goal of addressing long-standing questions regarding the role of spatial and temporal inputs and stochastic noise in triggering the signaling pathway. Preliminary data indicates that the synthetic lipid membrane platform provides for a more physiologically accurate approach to activate the Notch pathway in mammalian cell lines. A newly developed fluorescence force sensor will allow the direct measurement of the association between mechanical strain and protease activity. Microscopy-based single cell analysis of the transcriptional program will be used to measure ligand-induced activation. These experiments will yield a quantitative description of the pathway and may help in understanding the role of molecular Notch deregulations in human cancers.